Hydraulic shock absorbing device



March 6, 1962 w. M. KELLER 3,023,915

HYDRAULIC SHOCK ABSORBING DEVICE Filed Nov. 6, 1959 2 Sheets-Sheet 1 BYMLCSZL March 6, 1962 w. M.'KEL| ER 3,023,915

HYDRAULIC SHOCK ABSCRBINC DEVICE:

Filed Nov. e, 1959 2 sheets-sheet 2 INV EN TOR.

United States Patent O M 3,023,915 HYDRAULEC SHCK ABSORBING DEVICE William M. Keller, Evanston, Ill. (8864 E. Prairie Road, Skokie, lll.) Filed Nov. 6, 1959, Ser. No. 851,418 14 Claims. (Cl. 213-31) ri`his invention relates to hydraulic impact or shock absorbing devices and particularly to a device which 1s adapted for use as a railway car draft gear. Wh1le my invention is described in connection with a railway draft gear, the invention is not confined to this use but may be utilized in other cases where it is desired to absorb and cushion shocks.

lt is an object of this invention to produce a shock absorbing device capable of absorbing large forces or shocks through the combination of hydraulic means and friction means.

It is a further object of the invention to prov1de a shock absorbing device capable of efficiently functioning as a railway car draft gear under the high velocity impacts of present day railroad practice.

Another object of the invention is to provide an improved railway draft gear which can be used inthe standard draft gear pocket common in American railroad practice and can also be readily modified to t draft gear pockets of other dimensions.

A still further object of the invention is to provide a shock absorbing device having completely sealed hydraulic units so as to reduce and eliminate the problem of fluid leakage encountered in previously developed hydraulic draft gears which include piston rods, stufllng boxes, packing glands, etc.

Further objects and advantages of the invention will become apparent as the disclosure proceeds and the description is read in conjunction with the accompanying drawings in which:

FIG. l is a plan view partially in cross section showing my improved shock absorbing device disposed in a draft gear pocket in a neutral position, not subjected to either draft or bufling forces.

FIG. 2 is a view similar to FIG. l, but illustrates the position of the improved hydraulic draft gear when subjected to an initial buff force.

FIG. 3 is a view similar to FIG. l, but shows the position of my improved draft gear at the limit of travel under buff force.

FIG. 4 is a cross section view taken on line 4 4 of FIG. 1.

FIG. 5 is an exploded view showing the preferred arrangement of components of my improved shock absorbing device.

FIG. 6 is a perspective view of a modified form of the outer segmental sleeve used in my improved shock absorbing device.

Referring now in detail to the drawings, in which like reference characters designate like parts, my improved shock absorbing device is shown disposed in a railway car draft gear pocket, generally identified as 10, formed between the front stop lugs 11 and rear stop lugs 12 on a railway car center sill 13. My invention can be used in the standard draft gear pocket common in American railroad practice and which has a length of 24S/s" as mentioned on page 676 and as illustrated, for example, on page 702 of the Car Builders Cyclopedia, 20th edition, published in 1957 by Simmons-Boardman Publishing Corporation of New York, N Y. However, in this connection it should be noted that the dimensions of my improved shock absorbing device can be modified and the device readily adapted to fit into draft gear pockets having dimensions different from those of thev standard draft gear pocket.

3,923,915 Fatenteel Mar. 6, 1962 lCC My improved shock absorbing device is adapted to cushion both car pushing and car pulling shocks transmitted to it by the yoke 14 illustrated by dotted lines in FIGS. l to 3, inclusive. The yoke 14 is of suitable construction and is secured to a coupler shank, not shown, in a suitable manner.

Referring now particularly to FIGS. 1 and 5 of the drawings, it can be seen that the draft gear embodying my invention includes draft gear holder 15 open at one end as at 16, and having a centrally disposed longitudinal chamber 17 with an inner cylindrical wall 18 and end Wall 19. The open end of draft gear holder 15 is directed toward front stop lugs 11 and the outer face 20 of end wall 19 bears against rear stop lugs 12 as illustrated in FIGS. l to 3, inclusive, when the draft gear is in neutral position or is subjected to buff forces. An outer segmental sleeve generally indicated at 21 may be composed of two or more segments. FIGS. 4 and 5 show the sleeve formed of three segments. Each segment has a curved longitudinally extending wall portion 22 designed to telescopically slide within chamber 17 of draft gear holder 15. Each wall portion 22 terminates at one end in a collar 23 and each collar has an outer wall 24, an inner wall 25 directed radially outward from the longitudinal extending wall portion 22 and an aligned inner wall 26 directed radially inward from the wall portion 22.

If desired, a plurality of keys or small segments generally shown in FIG. 6, may be disposed in the spaces between the larger segments of the segmental sleeve. Each key has a longitudinally extending wall portion 27 and collar 28 adapted to match the associated walls and collars of segmental sleeve 21.

A follower 29 of disk-like shape bears against the radial inner wall portions 26 of collars 23 and closes the collar end of the assembled segmental sleeve. A spring guide and buffer shown generally at 30 in FIG. 5 has a disk-like portion 31 designed to slide within the longitudinally extending wall portions 22 of the segmental sleeve and also has a centrally located post 32 directed toward an aligned circular post 33 extending from the end wall 19 of draft gear holder 15. A helical spring 34 is positioned between the spring guide and buffer 30 and end Wall 19 and is guided on post portions 32 and 33. A plurality of contiguous hollow flexible cases or disks 35 containing hydraulic fluid 36 and formed with side wall portions 37 and peripheral walls 38 are disposed between the spring guide and buffer 30 and follower 29. These flexible disks 35 are made of rubber, rubber compounds, synthetic rubber or other suitable flexible material which is durable and tough and has the capacity to expand without rupture when subjected to pressure. The hollow disks 35 may be radially confined within a split sleeve 39 which is slidably received within segmental sleeve 21 and functions to protect the peripheral walls of the flexible disks 35 during operation of the device. lt should be noted, as illustrated at FIG. l of the drawings, when the draft gear is in neutral position, the overall length of split sleeve 39 is slightly less than the combined length of the fluid filled flexible disks. As thus arranged the inner split sleeve 39 4is positioned concentrically within the outer segmental sleeve 21.

It can be seen from an inspection of the arrangement disclosed in FIG. 1 of the drawings that the helical spring 34 coacts between the end wall 19 of draft gear holder 15 and the spring guide and buffer 30 to force the outer walls 24 of the outer sleeve segments into engagement with front stop lugs 11 and to force the outer face 20 of end wall 19 of draft gear holder 15 against the rear stop lugs 12 when the draft gear is not subjected to draft or buff forces. The force exerted by spring 34 against spring guide and buffer 30 is transmitted through the flexible disks 35 to follower 29 and from follower 29 to the inner wall portions 26 of collars 23 on the segments of the outer sleeve 21.

My improved hydraulic draft gear operates in the following manner. and 3 it should be be noted that the arrows indicate the direction of application of a push or buff force. This buff force is transmitted through the yoke 14 to outer wall 24 on collars 23 of the segmental sleeve 21 and results in a movement of this service to the right as viewed in FIGS. 2 and 3. As the segmental sleeve is moved to the right, follower 29 transmits the buff force through the flexible disks 35 to spring guide and buffer 30. Movement of spring guide and buffer 30 to the right causes helical spring 34 to be compressed. As the yoke 14, acting through the outer segmental sleeve 21, moves the assembly of parts towards the right, exible disks 35 are subjected to a longitudinal force and due to the fact that the hydraulic fluid 36 contained therein is practically incompressible, the peripheral Walls 38 of the liexible disks 35 are expanded radially by the iiuid and force the walls of inner split sleeve 39 into frictional engagement with the containing walls 22 of the outer segmental sleeve 21. In turn the wall portions 22 of the outer sleeve are forced into frictional contact with the wall 18 of longitudinal chamber 17. This causes a frictional drag between the outer segmental sleeve 21 and the draft gear holder 15. Further movement of the sleeve 21 to the right relative to this draft gear holder finally results in surface 40 at the end of post 32 making solid contact with surface 41 at the end of post portion 33. When such contact is made the full force of buff is applied as longitudinal pressure to the flexible disks 35 with a consequent sudden increase in the radial pressure being exerted by the contained liuid 36 against the peripheral walls 38 of disks 35. As a result, the wall portions 22 of the outer segmental sleeve 21 are urged tightly against the confining wall 18 of the draft gear holder and maintain this frictional contact throughout the remainder of the buff force application. The final limit of draft gear operation is reached, as shown in FIG. 3 of the drawings, when the inner walls 25 on the collars 23 of the outer segmental sleeve 21 make solid contact with the end wall 42 of draft gear holder 15.

In a draft force or pull application the process described under a push or buff force is essentially the same. However, in the case of a draft force the yoke 14, indicated on the drawings by dotted lines, contacts end wall 19 of draft gear holder 15 and the reaction to the draft force is taken on the front stop lugs 11. The internal parts of the draft gear function as under buff forces but the draft gear holder 15 moves over outer segmental sleeve 21 rather than the outer sleeve moving into the draft gear holder as it does in buff.

The hydraulic principle embodied in the present invention affords a practical means of shock absorption to protect railroad cars from sudden impact shocks of high magnitude on the car couplers. Hydraulic draft gears of the prior art include cylinders, pistons, piston rods, crossheads and guides to keep the piston and piston rod in proper alignment with the cylinder, stuffing boxes and other components requiring frequent inspection, service and replacement. This invention overcomes the uneconomical aspects of such prior art devices. In my invention, hollow flexible disks, filled with a suitable hydraulic iiuid cooperate with a split sleeve, outer segmental sleeve and draft gear holder, preferably made of hardened steel. In draft or buff the hydraulic fluid within the disks transmits pressure to the friction surfaces as previously described.

The foregoing description of my invention is made for the purpose of disclosure and to illustrate the principles involved, and will suggest various substitutions and changes that may be made under my basic concept. The

Referring particularly to FIGS. 2-

right is reserved to all such substitutions and modifications that lie within the scope of the appended claims.

I claim:

1. A shock absorbing device comprising a draft gear holder having an open end adapted to receive a segmental sleeve encircling a plurality of fluid filled disks confined between a follower within the segmental sleeve at one end thereof and a buffer member slidably received within the other end of said segmental sleeve, whereby upon application of a longitudinal force to either the follower or the buffer member radial forces will be exerted against the peripheral walls of said fluid lled disks which in turn radially expand said segmental sleeve into frictional contact with the inner wall of said draft gear holder.

2. The shock absorbing device defined by claim l wherein a split sleeve is positioned between the peripheries of the iiuid filled disks and the said segmental sleeve..

3. The shock absorbing device defined by claim 1 wherein a split sleeve is positioned between the peripheries of the fluid filled disks and the segmental sleeve. and a spring is disposed between the buffer member and the end wall of the draft gear holder.

4. In a shock absorbing device a draft gear holder, a segmental sleeve longitudinally disposed in open end to end relation with said holder and telescopically slidable therein, the longitudinally extending walls of said segmental sleeve being radially expansible, a plurality of flexible disks each of which completely encloses a Huid medium therein, said disks being disposed in continuous relationship within said sleeve, the peripheral walls of said fiexible disks being operatively associated with said longitudinally extending walls, said disks being longitudinally confined between a follower held at one end of said segmental sleeve and a member slidable within the walls of said segmental sleeve at the opposite end thereof, means disposed between the end wall of said draft gear holder and said member, whereby upon the application of a longitudinal force to the device which tends to move the draft gear holder relative to the segmental sleeve, said means will urge said member toward the follower to thereby radially expand said fiexible disks and force the walls of said segmental sleeve into progressive frictional contact with said draft gear holder.

5. A shock absorbing device comprising a draft gear holder, a segmental sleeve disposed in open end to end relation with this holder and telescopically slidable therein, the longitudinally extending walls of said segmental sleeve being radially expansible into frictional coi'ltact with said draft gear holder, means for expanding the walls of said segmental sleeve, said means including a plurality of contiguous flexible disks the peripheral walls of which are associated with said longitudinally extending walls, each flexible disk completely encasing a iiuid medium, said flexible disks being longitudinally confined between a follower held' at one end of the segmental sleeve and a member slidable within said walls of said sleeve at the other end thereof, means operatively disposed between said member and the end wall of said draft gear holder whereby upon the application of an external longitudinal force tending to move the draft gear holder and' segmental sleeve relative to each other, said last named means will urge said slidable member toward the follower to thereby exert longitudinal pressure in progressive increasing amounts against said iiexible disks with a resultant radial expansion thereof to urge the walls of said segmental sleeve into increasing frictional engagement with said draft gear holder.

6. A shock absorbing device comprising a draft gear holder in the form of a casing open at one end and closed at the opposite end by end wall, a segmental sleeve disposed in open end to end relation with said draft gear holder and telescopically slidable therein, the longitudinally extending walls of said segmental sleeve being radially expansible into frictional contact with said draft gear holder, a split sleeve concentrically associated with said walls, means for expanding said walls of said segmental sleeve which includes a plurality of flexible hollow disks filled with a fluid medium, the peripheral walls of said disks being confined by said split sleeve and said disks being assembled longitudinally in contiguous relationship with one side of the assembly in contact with a follower held at one end of the segmental sleeve, a member slidable within the walls of said segmental sleeve at the other end thereof, the member being in contact with the other side of the assembled flexible disks, means disposed between the end wall of said draft gear holder and said member whereby upon an application of longitudinal force against the device which tends to move the draft gear holder relative to the segmental sleeve, the last named means urges said member towards the follower to exert longitudinal pressure in progressively increasing increments against said flexible disks with a resultant radial expansion of the peripheral walls of said disks which urges the walls of said segmental sleeve into increasing frictional engagement with said draft gear holder.

7. In a shock absorbing device having a draft gear holder open at one end, a segmental sleeve telescopically received in said draft gear holder in open end to end relationship, the longitudinally extending walls of said segmental sleeve being radially expansible into frictional engagement with the surrounding walls of the draft gear holder, means for expanding the walls of said sleeve upon the application of an external longitudinal force to the device which tends to move the draft gear holder relative to the segmental sleeve, said means including a plurality of contiguous hollow flexible members each of which is lled with an hydraulic fluid, the peripheral Walls of said flexible members being operatively associated with the longitudinally extending walls of said segmental sleeve, resilient means disposed between the end wall of the draft gear holder and a member slidable Within the longitudinally extending walls of the segmental sleeve at the open end thereof, said flexible members being confined between a follower held at one end of the segmental sleeve and said slidable member, said slidable member having a portion spaced from said end wall of the draft gear holder, whereby during the initial period of an external force application tending to move said draft gear holder relative to the segmental sleeve the resilient means is compressed and urges said slidable member against said flexible members to cause said segmental sleeve to be radially expanded into frictional engagement with said draft gear holder and whereby after the desired compression of the resilient means said slidable member makes solid contact with said draft gear holder and the full external force is applied directly through said slidable member to said flexible members to urge said segmental sleeve into increased frictional engagement with said draft gear holder during the remaining period of external force application.

8. In a shock absorbing device a draft gear holder iu the form of a casing open at one end and closed at the other end by an end wall, a segmental sleeve longitudinally disposed in open end to end relation with said draft gear holder and telescopically slidable therein, the longitudinally extending walls of said segmental sleeve being radially expansible into frictional engagement with said draft gear holder, means for expanding the walls of said segmental sleeve which includes a plurality of fiexible hollow disks longitudinally disposed in contiguous relationship within said segmental sleeve, said flexible disks being radially associated with said walls and being confined at one side by a follower held at one end of said segmental sleeve, each of said disks being completely filled with an hydraulic fluid, a member slidable within the walls of said segmental sleeve at the open end thereof, and operative means disposed between said slidable member and the end wall of said draft gear holder to maintain said member in engagement with the other side of said disks.

9. In a shock absorbing device a draft gear holder of casing-like form open at one end and closed at the other end by an end wall, a segmental sleeve longitudinally disposed in open end to end relation with said draft gear holder and telescopically slidable therein, the longitudinally extending walls of said segmental sleeve being radially expansible into frictional engagement with said draft lgear holder, means disposed within the walls of said segmental sleeve for expanding said walls upon relative longitudinal movement between said draft gear holder and segmental sleeve, said means including a plurality of flexible disks, each of said disks being completely filled with a fluid medium, said disks being longitudinally disposed in contiguous relationship between a follower held at one end of said segmental sleeve and a member slidable within the walls of said sleeve at the open end thereof, and a spring disposed between said slidable member and the end wall of said draft gear holder.

10. A shock absorbing device adapted to be mounted in the draft gear pocket of a railroad car, said pocket including spaced front and rear stop lugs, a draft gear holder having a closed end and an open end, the holder having inwardly facing longitudinally extending friction surfaces; a segmental sleeve having longitudinally extending wall portions received concentrically within the draft gear holder, a radially disposed collar at one end of the segmental sleeve, which collar engages the front stop lugs when the draft gear is in neutral position, a plurality of fluid filled disks confined within said segmental sleeve by a follower at the collar end and a spring guide and buffer slidable within said segmental sleeve at the opposite end thereof, a spring positioned between the spring guide and the end wall ofthe draft gear holder, the end wall of the draft gear holder being in contact with said rear stop lugs when the draft gear is in neutral position, not subjected to buff or draft forces.

1l. A draft gear including a plurality of fluid filled flexible disks confined between a follower and a buffer, the peripheral walls of said disks, said follower and said buier being surrounded by an outer segmental sleeve having longitudinally extending wall portions disposed within a draft gear holder, whereby buff or draft forces effect radial pressure upon the peripheral walls of said disks to thereby urge the said longitudinal walls of the outer segmental sleeve into frictional contact with the inner wall of the draft gear holder.

12. The draft gear defined by claim l1 wherein a split sleeve is disposed concentrically between the peripheral walls of the flexible disks and the longitudinal walls of the segmental sleeve.

13. The draft gear defined by claim 11 wherein keys are disposed between the respective segments of the said outer segmental sleeve.

14. The draft gear defined by claim 1l wherein one end of the outer segmental sleeve terminates in a collar having a portion against which said follower abuts.

Campbell Aug. 28, 1956 Alldredge et al. Apr. 15, 1958 UNITED STATES PATENT OFFICE CERTIFICATE 0F CGRRECTION Patent No, 3,023,915 March 6l 1962 William Mra Keller hat error appears in the above numbered pat- It is hereby certified t hat the said Letters Patent should read as ent requiring correction and t corrected below.

Column 3v line l0, for "service" read sleeve column 4, line BO, for "continuous" read contiguous --5 line 72, after "by" insert an Signed and sealed this 3rd day 0f July l92 (SEAL) LttCSl:

DAVID L. LADD RNEST W. SWIDER Commissioner of Patents meeting Officer 

